Why I use Internet Explorer

Back in June, The Register screamed that US-CERT recommends not using Internet Explorer. Why in the face of a never ending cycle of patches would someone continue to use Microsoft Internet Explorer? Here’s what I’ve been able to put together.
1. Business Use Case
Internet Explorer is the best browser for use with our intranet which uses Sharepoint and our future use of Microsoft Project. Alternative browsers do not have the same feature rich experience when dealing with Sharepoint and OWA. Additionally the integrated windows authentication would not be available with other browsers.
2. Ease of updates
Currently updates for Internet Explorer are performed using the SMS SUS FP. Its rather easy. Operating System patches and Internet Explorer patches can be done at one time. Third party browsers often require an install of a new version rather than a patch.
3. Vulnerabilities in alternative browsers are increasing in occurrence and severity.
4. User Education
Switching browsers doesn’t address the true problem, the educated user.
5. Usability
Internet Explorer as the dominant browser works on most sites.
6. Manageability
Internet Explorer is enterprise ready. It can be configured via Group Policy. How will you centrally manage a third party browser.
7. Support
Who supports the third party browser? We would go from being Microsoft Premier customers to relying on newsgroups for help.